Annotations Instead of XML

An XML-Free Mapper

For simple statements, MyBatis lets you put SQL directly on the interface with annotations - no XML file needed.

public interface CustomerMapper {

  @Select("SELECT * FROM customers WHERE id = #{id}")
  Customer findById(Long id);

  @Select("SELECT * FROM customers WHERE city = #{city}")
  List<Customer> findByCity(String city);

  @Insert("INSERT INTO customers (name, email, city)
          VALUES (#{name}, #{email}, #{city})")
  @Options(useGeneratedKeys = true, keyProperty = "id")
  void insert(Customer customer);

  @Update("UPDATE customers SET city = #{city} WHERE id = #{id}")
  int updateCity(@Param("id") Long id, @Param("city") String city);

  @Delete("DELETE FROM customers WHERE id = #{id}")
  int delete(Long id);
}

When Annotations Work Well

• Short, stable CRUD statements.
• No dynamic SQL required.
• You prefer reading SQL next to the method.

When to Keep XML

• Long queries with dynamic SQL and result maps.
• Complex nested associations.
• Report queries over a hundred lines.

XML handles the hard cases; annotations stay tidy for the easy ones. You may mix both per mapper.

Key Points

• @Select, @Insert, @Update, @Delete inline the SQL.
• @Options pulls generated keys into the entity.
• Annotations suit short, static statements.
• Keep XML for dynamic and complex queries.